﻿Diptera, 
  Hemiptera 
  and 
  Insects 
  related 
  to 
  Neuroptera. 
  105 
  

  

  order. 
  The 
  lines 
  of 
  descent 
  of 
  the 
  Hemiptera 
  and 
  Homo- 
  

   ptera 
  have 
  therefore 
  been 
  represented 
  in 
  the 
  diagram 
  as 
  

   though 
  occupying 
  a 
  position 
  intermediate 
  between 
  the 
  

   insects 
  grouped 
  about 
  the 
  Neuroptera 
  and 
  those 
  grouped 
  

   about 
  the 
  Psocidae, 
  being 
  shghtly 
  nearer 
  the 
  latter 
  than 
  

   the 
  former. 
  

  

  The 
  Hymenoptera 
  are 
  here 
  treated 
  as 
  though 
  consti- 
  

   tuting 
  a 
  single 
  order; 
  but 
  there 
  are 
  some 
  grounds 
  for 
  

   considering 
  the 
  sawfly 
  group, 
  or 
  chalastogastrous 
  Hymeno- 
  

   ptera 
  (including 
  the 
  suborder 
  Idiogastra 
  of 
  Rohwer, 
  1917, 
  

   Proc. 
  Ent. 
  Soc. 
  Washington, 
  vol. 
  19, 
  p. 
  92) 
  as 
  a 
  distinct 
  

   order, 
  called 
  Pro 
  hymenoptera 
  by 
  Crampton, 
  1916 
  (Ent. 
  

   News, 
  vol. 
  27, 
  p. 
  303), 
  or 
  Bomboptera 
  by 
  MacLeay, 
  1829 
  

   (applied 
  to 
  the 
  " 
  Uroceridae 
  " 
  alone). 
  Rohwer, 
  1917 
  

   (I.e.), 
  however, 
  points 
  out 
  the 
  annectant 
  character 
  of 
  the 
  

   Oryssoid 
  sawflies 
  between 
  the 
  Siricoid 
  members 
  of 
  the 
  

   sawflies 
  and 
  the 
  Braconids, 
  etc., 
  among 
  the 
  higher 
  Hymeno- 
  

   ptera, 
  maintaining 
  that 
  this 
  connection 
  between 
  the 
  two 
  

   groups 
  unites 
  them 
  into 
  one 
  homogeneous 
  order. 
  When 
  

   one 
  has 
  examined 
  such 
  " 
  synthetic 
  " 
  types 
  as 
  the 
  Micro- 
  

   pterygidae, 
  Zoraptera, 
  Grylloblattids, 
  Isoptera, 
  etc., 
  which 
  

   combine 
  in 
  themselves 
  characters 
  common 
  to 
  several 
  other 
  

   orders 
  of 
  insects, 
  it 
  is 
  at 
  once 
  apparent 
  that 
  the 
  existence 
  

   of 
  these 
  connecting 
  forms 
  does 
  not 
  invahdate 
  the 
  distinct 
  

   orders 
  which 
  they 
  serve 
  to 
  connect 
  (and 
  indeed, 
  at 
  one 
  

   time, 
  all 
  of 
  the 
  orders 
  must 
  have 
  been 
  connected 
  by 
  such 
  

   intermediate 
  forms), 
  so 
  that 
  Rohwer's 
  objection 
  to 
  the 
  

   division 
  of 
  the 
  Hymenoptera 
  on 
  this 
  score, 
  does 
  not 
  hold 
  

   good. 
  For 
  the 
  sake 
  of 
  convenience, 
  however, 
  they 
  are 
  

   treated 
  as 
  a 
  single 
  order 
  in 
  the 
  present 
  discussion. 
  

  

  Ashmead, 
  1895 
  (Proc. 
  Ent. 
  Soc, 
  Washington, 
  vol. 
  3, 
  

   p. 
  330), 
  has 
  summarised 
  the 
  different 
  views 
  as 
  to 
  the 
  re- 
  

   lationships 
  of 
  the 
  Hymenoptera, 
  as 
  follows 
  : 
  " 
  Latreille 
  

   placed 
  it 
  (the 
  order 
  Hymenoptera) 
  between 
  the 
  Neuroptera 
  

   and 
  the 
  Lepidoptera, 
  regarding 
  Phryganea 
  and 
  Termes 
  as 
  

   forming 
  the 
  hnk 
  between 
  them, 
  considering 
  the 
  long- 
  

   tongue 
  bees 
  as 
  approaching 
  nearest 
  to 
  the 
  Lepidoptera. 
  

   MacLeay, 
  on 
  the 
  other 
  hand, 
  placed 
  the 
  Plymenoptera 
  

   between 
  the 
  Coleoptera 
  (with 
  which 
  they 
  are 
  supposed 
  

   to 
  be 
  connected 
  by 
  the 
  osculant 
  order 
  Strepsiptera) 
  and 
  

   the 
  Trichoptera, 
  the 
  Tenthredinidae 
  being 
  considered 
  as 
  

   Trichopterous 
  and 
  the 
  Uroceridae 
  as 
  forming 
  an 
  osculant 
  

   order 
  Bomboptera, 
  between 
  Trichoptera 
  and 
  Hymenoptera, 
  

   which 
  last 
  order 
  is 
  reduced 
  to 
  the 
  species 
  possessing 
  apodal 
  

  

  